Ischemic heart disease and mitral valve disease are examples of conditions that cause the atrial myocardium to degrade. Ischemic heart disease leads to infarcted tissue within the atrial myocardium, and mitral valve disease leads to dilation and weakening of the atrial myocardium. Degradation of the atrial myocardium through these and other disease mechanisms can lead to patient discomfort and reduction in cardiac performance.
For example, both ischemic heart disease and atrial dilation may result in the onset of paroxysmal atrial fibrillation. The disorganized contractions of the atria during an episode of fibrillation are insufficient for proper ventricular filling, and atrial fibrillation can consequently lead to patient symptoms such as dizziness and shortness of breath. Atrial fibrillation is also conducive to the formation of potentially life-threatening emboli. Further, ischemic heart disease of the ventricles can lead to angina pectoris, which may occur spontaneously, or during periods of exercise or strong emotions.